The North American Electric Reliability Corporation (NERC) promulgates standards directed to maintaining the reliability of the electric power grid infrastructure. For example, NERC standard PRC-005-2, which is incorporated herein by reference, sets forth required testing timelines for testing direct current (DC) systems of a power utility, for example DC relay systems located at a power utility substation. Such DC relay systems often include a backup service battery system. Such a backup service battery system is often, but not necessarily, a stationary system having a battery charger that maintains the battery fully charged and supplies power to the DC load under normal operation. In the event that supply power is lost to the battery charger, the backup service system switches to battery power to supply uninterrupted power to the DC load. Thus, the DC relays at a power substation might maintain power to provide power switching in the event of an emergency condition, such as a blackout or brownout. The batteries employed in such systems are typically either vented lead acid (VLA) batteries or Valve-Regulated Lead Acid (VRLA) batteries. The Institute of Electrical and Electronics Engineers (IEEE) has promulgated a standard for battery integrity testing, IEEE 450-2010, which is incorporated herein by reference, that provides standard procedures for maintenance and testing procedures to optimize the life and performance of permanently installed VLA storage batteries used for backup service, for example as backup power to DC relays in power switching applications at a power utility substation.
NERC PRC-005-2 requires that specified tests be performed at specified time intervals. For example, under NERC PRC-005-2, every four calendar months the utility must verify the DC supply voltage of the battery system, inspect electrolyte level of the batteries, and check for ground faults. Every 18 calendar months, the utility must verify the float voltage of the battery charger, the continuity of all battery cells, battery terminal connection resistance, battery inter-cell or unit-to-unit connection resistance and visually inspect the batteries. Finally, every six calendar years, the utility must verify battery performance by conducting a capacity test of the entire battery bank. However, to currently perform such tests, a technician must visit each physical substation location, and typically perform tests by manually connecting test equipment to the system. This can be both dangerous to the technician and time-consuming. Further, many substations, especially geographically remote substations and/or older substations do not support much, if any, data communication between the substation and a central control facility. For example, the oldest and/or most remote substations might not have any data communication with a central control facility. Slightly more modern substations might only support one or more contact closure connections that might only communicate data in one direction (e.g., from the substation to a central control), and might not provide much information beyond informing the utility to send a technician to manually diagnose an issue. More recently, utility companies having been employing Supervisory Control and Data Acquisition (SCADA) systems in new substations to communicate data between the substation and a central control facility, that might acquire, aggregate and communicate data from the substation to a central control facility. However, the types of data supplied in current SCADA systems is limited, and the performance of tests in accordance with either NERC PRC-005-2 or IEEE 450-2010 still require a technician be physically present to manually perform tests.
Thus, improved systems are needed to remotely test and monitor the status of the backup service system and batteries, and report the test results and system status to a remote location, while providing backward compatibility to older utility infrastructure.